Knuckle joint lock



Dec. 8, 1942.

E. L. Po'rTs 2,304,119

KNUCKLE JOINT LOCK Filed Oct. 50, 1939 2 Sheets-Sheet l :E'.L.F'- 17 1.H5-

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" Dec. 8, 1942.

E. L. Po'rTs 2,304,119

KNUCKLE JOINT LOCK Filed Oct. 30, 1959 2 Sheets-Sheet -2 5 as j 22 I I17 \8 v 3 15 5| so 54 v) 35 I e 58 F E.L.PoT-rs g'nve nl'orl. (Y

Patente d Dec. 8, 1942 UNETED STTFE- OFFICE KNUCKLE JOINT LOCK Ernest.L. Potts, Houston, Tex., assignor to Fullgage Deflecting Tool Company,Houston,

Tex a corporation Claims.

The invention relates to an improvement in deflecting tools of the typewhich may be used in drilling a well bore at an inclination with respectto the axis of the drill stem in the rotary method of drilling.

In well deflecting and straightening operations it is often necessary toincline the drill bit with respect to the drill stem so that the wellbore may be deflected to provide an inclination with respect to theoriginal well bore. To accomplish this various types of deflecting toolshave been developed wherein a universal or knuckle joint, as they aregenerally known in the .fleld,

is used to connect the drill bit to the drill stem,

so that the drill bit can be inclined and the drilling operationinstituted and carried on with the bit in this inclined position. Theknuckle joint must transmit rotation from the drill stem to the drillbit. The present invention adapts itself to this type of jointconnection and provides for locking the connection is a predeterminedinclined direction relative to the drill stem so that the drill bit willremain in this predetermined position until the drilling operation is tobe instituted. This insures that the 'bit will arrive at the point wherethe deflection .is to be made in the proper position and inclination andcan be thereafter released.

It is one of the objects of the invention to provide a lock for knucklejoints which can be released by fluid pressure.

Another object is to provide a means and meth- 0d of deflecting a wellbore in a single operation whereby a survey to orient the tool, thedeflecting operation to drill a full gage bore, and a subsequent surveycan all be made without Withdrawing the deflecting tool.

Another object of the invention is to provide a movable plunger whichwill release a knuckle joint lock in drill stems.

Another object of the invention is :to provide an arrangement whereby adrill bit is locked in a predetermined inclined. oriented positionrelative to the drill stem until such time as the bit has been spuddedinto the formation whereupon the lock can be released and the drilling:operation carried on.

Another object of the invention .is to provide a fluid pressure operatedlocking device for knuckle joints which will transmit a signal to theoperator at the surface by a reduction in fluid pressure when the lockis released.

Other and further objects of the invention will be readily apparent whenthe following description is considered in connection with theaccompanying drawings wherein:

Fig. 1 is a vertical sectional view of the knuckle joint as it arrivesin position at the bottom of the well bore with the bit locked in aninclined position.

Fig. 2 is a section taken on the line 2--2 of Fig. l and looking in thedirection of the arrows. v

Fig. 3 is a vertical sectional view of the bit after the drillingoperation has progressed somewhat and shows the locking device released.

Fig. 4 is a vertical sectional view of another form of the same tool.

In Fig. 1 a well bore 2 is to be deflected at :an angle with respect toits axis and to accomplish this a drill bit 3 connected to a sub 4 and aknuckle joint 5 has been lowered into the well bore by means of a drillstem 6.

It should be noted that the coupling A .and the drill bit 3 are inclinedwith respect to the axis of the drill stem and that this inclination ispermitted by virtue of the construction of the knuckle joint 5.

in deflecting well bores in the manner about to be described it isusually desirable to know the direction of the deflection so that it isdesirable to arrange the drill bit 3 in a predetermined inclinedposition relative to the drill stem 6. The drill stem 6 can then beoriented into the hole so that the direction of inclination of the bitis known, or various types of surveying devices may be utilized inorienting the pipe in the hole after it has been lowered into position.Irrespective, however, of the method or apparatus which is used indetermining the orientation of the drill bit it is desirable .to retainthe drill bit in a definite fixed position from the time it leaves thesurface until the time 'it arrives upon the bottom 8 of the well bore 2and such aconstruction is embodied in the structure of Fig. l.

The, knuckle joint 5 includes an outer housing 9 which may carry reamerblades Ii] thereon. This housing is threaded at I l to receive the sub 4which carries the drill bit 3.

The inside of the housing 9 is hollow and carries a plurality ofcircumferentially arranged ribs I? which have interfitting therewith theribs 13 which are provided on a drive bushing l5, which is disposedinside .of the hollow housing 9. This bushing l5 has an enlarged head 16thereon which fits against a shoulder it inside of the housing.

The upper surface of the head l6 has a plurality of spaced teeth orgear-like members I8 which interfit with similar members H on the lowerend of the member I 9 which forms part of the knuckle joint. In thismanner the bushing I and the members i9 and iii are non-rotatablyconnected but they can tilt angularly with respect to each other due tothe length of the interfitting teeth or gears l8 and i9. As seen in Fig.1, the teeth at the left of the center line will interflt while those onthe right of the center line are drawn apart by the tilting of thebushing i5. A gland member is threaded into the upper end of the housingand holds the bushing I5 in position. This gland 2ilhasa curved socketportion 2!, which receives the curved ball 15 area 22 on the member l9,so that a ball and socket or universal joint is in this manner providedwhich will permit limited tilting of the bushing 55 relative to themember 19, because of the fact that the opening 25 in the gland 20 is Henlarged to permit it to tilt as seen in Fig. 1.

It seems obvious that the foregoing knuckle joint connection willtransmit rotation while permitting tilting of the drill bit with respectto the drill stem.

As pointed out heretofore it is desirable to lock the drill bit 3 in apredetermined inclined direction prior to the time that it is loweredinto the well bore. To accomplish this a seat member is threaded intothe lower end of the member i9 30 and this seat member carries aninclined seat 3|, which is conical in construction and has the passage32 therethrough. This passage merges with the passage 33 in the upperend of the knuckle joint so that a flow of flushing fluid may be 5pumped downwardly through the tool. A similar passage 34 passes to thedrill bit.

Particular attention is directed to the inclination of the seat 3| withrespect to the axis of the tool, as will be particularly noted fromFigs. 1, 3 and 3.

A plunger 35 is slidably arranged in an opening in the bushing l5 andthis plunger has a tapered upper end 36 which is arranged to engage inthe seat 3!. This tapered end is sym-y metrical, however, with the aXisof the plunger and the axis of the sub 3 and the bit 3. A coiled spring48 is seated inside of the housing 9 and normally urges the plunger 35upwardly into the seat 3|. Thus the inherent resiliency of this 50spring forces the plunger onto its seat and would normally throw thedrill bit off the inclination at which the seat 3i is inclined withrespect to the drill stem. Of course, the bushing 30 may be arranged inthe drill stem so that the seat is inclined at any desired angle anddifierent types of bushings may be inserted so as to incline the bit atthe desired angle for any particular set of circumstances.

The plunger 35 has a choke or small passage-. 31 therethrough whichjoins the passages 32 and 3 L This passage 31 is of such a size thatthere may be some flow of fluid therethrough but it serves as arestriction for a full flow of fluid. An additional passage 4! ext-endsin an inclined po g sition through the plunger 35 and is open to a flowof circulation when the plunger is moved downwardly asis shown in Fig.3.

In operation the parts will be assembled as shown in Fig. 1 and loweredinto the well bore-("f The operator of course knows the inclination ofthe bit 3 with respect to the drill stem. The drill stem may be orientedin any desired manner one of which includes a magnet in the drill stem 6adjacent the deflecting tool and a detector iii-T7 strument to show theposition of such magnet. Such instrument may be run into and out of thedrill stem as desired. The tool is now dropped sharply so as to forcethe bit 3 into the bottom 8 of the well bore. This fixes the inclinationof the bit with respect to the drill stem. Durin this operation drillingmud or flushing fluid is forced downwardly through the drill stem andthrough the choke passage 31 so that the operator knows that he has apredetermined pressure applied to this fluid to maintain a circulation.After the bit has been spudded in position the operator can increase thepump pressure so as to increase the rate of circulation and in thismanner increase the pressure on the plunger 35. This increased pressureovercomes the spring iii) and moves the plunger down to the positionshown in Fig. 3. This opens up the knuckle joint so that there may be aflow through both the passages 31 and 4|. This combined flow is readilyindicated to the operator by the sound of his pumps or a flow gauge sothat he has a positive indication that the knuckle joint has beenunlocked.

Inasmuch as the bit has been seated in the formation now that the jointis unlocked rotation may be started and the bit will penetrate theformation as seen in Fig. 3. The circulation of fluid maintains the bitin unlocked position. The reamer blades ID are of substantially fullgage so as to drill a deflected bore of the full diameter so that nosubsequent reaming operation is necessary.

.One of the particular advantages of this construction is that itinsures the arrival of the bit on the well bottom in its proper inclinedposition. It permits the bit to be unlocked so that it may be used todeflect the well and then when the flow of flushing fluid is reduced thebit automati-' cally locks itself again in its inclined position becausethe plunger 35 is moved upwardly by the spring 40 and a slight amount ofrotation will cause the plunger to snap in against the seat 3i so thatthe bit is again locked. This construction is of advantage because itmay be desirable to make more than one deflection from the same settingand it is only necessary to again spud the bit into the well bore,unlock it by fluid circulation, and continue the drilling at anadditional inclination and furthermore there is notorque applied to thetool in unlatching it which might tend to turn the tool from itsoriented position.

Attention is directed to the fact that the pressure against the inclinedside or the plunger head 35 from the seat 3i, as indicated in Fig. I, isat a right angle with respect to the inclination of the head so that noamount of lateral pressure on the bit 3 could cause unlocking of thebit, and the bit can only be unlocked by an increase in fluid pressure.

Fig. 4 shows a slightly modified form of the deflecting tool wherein theparts are substantially the same as previously described except that thegland 20 is screwed onto the drive bushing l5 instead of into thehousing 9 and the housing in turn is screwed onto the lower end of thedrive bushing, which somewhat simplifies the manufacturing of the tool.7

The plunger construction 35 is somewhat like that. shown in Fig.l'except that the tapered upper end36 of the plunger does not have thepassage 3'! therethrough but such passage is provided at 50 in the headof the plunger to one side of the tapered portion 36. A packing ring orsealing element is provided around the plunger in the recess in thedrive bushing.

In order to more accurately control the pressure and the opening andclosing of the passage through the tool a support ring 52 has beenaffixed inside of the plunger and carries a seat 53 which is arranged toreceive the ball check valve 54. Fluid under pressure passing downwardlythrough the tool and the openings 58 will hold the ball 54 upon its seatso as to close the passage completely. The plunger 35 and the supportring 52 are yi'eldably mounted upon a pair of coil springs 55 whichproject downwardly into the housing 9. The pressure of these springsnormally urges the tapered portion 38 into the inclined seat 3| in theseat member 30.

Projecting upwardly from the inside of the housing 9 is a spindle 58which has openings 59 in the top thereof. This spindle is of such anelevation that when the plunger 35 moves downwardly it will engage theball check valve 54 and dislodge it from the seat 53. This opens up thetool to allow the circulation of liquid therethrough to wash thecuttings away from the bit. When the pressure is reduced and the plunger35 moves upwardly the valve 54 will again seat and prevent circulation.In this manner a more definite signal is given to the operator becauseof the positive closing of the passage through the tool.

In the form of the invention in both Figs. 1 and 4 attention is directedto the relative size of the reamer blades 19 in that they are ofsubstantially the same diameter as the well bore 2, so that as thedrilling progresses the deflecting hole will be drilled to substantiallyfull diameter or full-gage and in this manner the deflecting operationwill result in a full sized bore without withdrawing the deflecting tooland inserting a regulation drilling bit. This is of material advantagein regard to cost and delay in the deflecting operation, because afterdeflection has been completed the ordinary bit may be moved into thebottom of the hole without performing a separate and independent reamingoperation.

Broadly the invention contemplates a locking device for knuckle jointswhich can be released by fluid pressure and automaticallyre-locked bydiminishing the pressure.

What is claimed is:

1. A knuckle joint for drill stems including a ball and socketconnection, interfitting portions thereon to transmit rotation, a seatin said joint which is inclined with respect to the axis of the drillpipe, and movable means also in said joint to engage said seat andnormally look the joint in ofiset position, said last means including aspring pressed plunger, having a choke passage therethrough.

2. A knuckle joint for drill stems including a ball and socketconnection, interfltting portions thereon to transmit rotation, a seatin said joint which is inclined with respect to the axis of the drillpipe, and movable means also in said joint to engage said seat andnormally lock the joint in offset position, said last means including aspring pressed plunger, having a choke passage therethrough and anadditional passage to be opened when said plunger is unseated.

3. A knuckle joint for drill stems including a ball and socketconnection, interfitting portions thereon to transmit rotation, a seatin said joint which is inclined with respect to the axis of the drillpipe, and movable means also in said joint to engage said seat andnormally look the joint in offset position, said last means including aspring pressed plunger to be unseated by fluid pressure to release saidbit.

4. A locking device for ball and socket member joints to lock the jointat a predetermined inclination including a plunger member carried by onemember, an oil center seat therefor carried by the other member, meansto urge said plunger member against said seat to hold the joint in theoff center position of the seat, and a fluid passage through said seatto be opened when said plunger is unseated.

5. A locking device for ball and socket member joints to lock the jointat a predetermined inclination including a plunger member carried by onemember, an off center seat therefor carried by the other member, andmeans to urge said plunger member against said seat to hold the joint inthe 01f center position of the seat, said plunger member beingunseatable by fluid pressure passing the joint.

ERNEST L. PO'I'I'S.

